The present invention relates to a heterogeneous-systems coexistence method and a wireless gateway apparatus for allowing the utilization of one and the same frequency in a plurality of different white-spaces-utilized wireless communications systems. Here, each of these white-spaces-utilized wireless communications systems flexibly utilizes radio waves included within the white spaces, while sufficiently avoiding influences that are exerted onto already-existing operations (i.e., primary system, primary users, and primary-use system).
In recent years, as a novel frequency-utilizing method for solving the frequency's exhaustion problem, researches and developments have been made concerning the following white-spaces-utilized wireless communications system such as a cognitive-radio communications system: Namely, this white-spaces-utilized wireless communications system flexibly utilizes the radio waves included within the frequency bands (i.e., white spaces), while sufficiently avoiding the influences exerted onto the already-existing operations. Here, the white spaces are the frequency bands that are still available in time and space, although the bands have been pre-allocated already.
For example, the standardizations of this white-spaces-utilized wireless communications system are now underway in the IEEE802.22 (refer to Non-Patent Document 1) and the IEEE802.11af. In these standards, in order to avoid the influences exerted onto the already-existing operations (such as, e.g., TV broadcasting), the following requirements are specified:
1) Each wireless station makes an access to a white-spaces-managing database (i.e., Incumbent DB, white-space database, WSDB) on the IP network, or a network manager thereon. By making this access, each wireless station acquires an available frequency list and transmittable maximum power which are based on its own geolocation information, and
2) each wireless station performs its communications after making the following confirmation by using its spectrum-sensing function (i.e., signal-detecting function): Namely, it is confirmed that an already-existing station, which is using a frequency that is to be utilized by each wireless station, does not exist in its surroundings.
In order to effectively perform these acquisition and confirmation, consideration is now given to an idea that the bandwidth and channel deployment of each standard be made identical to those of the TV broadcasting.
By the way, the above-described respective standards differ from each other in their services that are targeted thereby. Namely, in the IEEE802.22, its object is to construct the WRAN (Wireless Regional Area Network) for covering a wide-scale area by using a long-distance wireless transmission. Meanwhile, in the IEEE802.11af, its object is to construct the WMAN (Wireless Metropolitan Area Network) for covering an intermediate-scale area, and the WLAN (Wireless Local Area Network) for covering a narrow-scale area by using an intermediate-or-short-distance wireless transmission. In these systems, consideration is now given to the following method, for example: Namely, the IEEE802.22 WRAN i.e., the long-distance wireless transmission facility, is used as a backhaul line for implementing the Internet connection; whereas the IEEE802.11af WLAN is used as the intermediate-or-short-distance wireless transmission facility for covering each intra-home or intra-city area. Accordingly, it is requested to devise and provide a control for allowing the two wireless networks of the IEEE802.22 and the IEEE802.11af to coexist with each other without interfering with each other (refer to, e.g., JP-A-2012-29177, JP-A-2011-193422, and JP-A-2011-176508, and Non-Patent Document 2).    [Non-Patent Document 1] Edited by the Institute of Electrical and Electronics Engineers (IEEE) Computer Society, “IEEE Std 802.22.2011 Part 22: Cognitive Wireless RAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications: Policies and Procedures for Operation in the TV Bands”, (United States), IEEE Standardization Association, Jul. 27, 2011    [Non-Patent Document 2] Tuncer Baykas, “IEEE802.19.1 Overview”, [online], IEEE802.19 Working Group